The present invention relates in general to compound relief valves and in particular to a pilot operated relief valve of the type which has a main valve including two control spaces, a main pressure port, a consumer port, and a main piston defining two end faces adjoining respectively the control spaces; one control space is connected to the consumer port and a pilot valve is connected between a source of control pressure and the other control space to move the main piston in one direction in which a communication between the main pressure port and the consumer port is established while pressure in the consumer port acts in counter direction.
In a known pressure relief valve of the abovedescribed type, a throttling point is established in the connection between the consumer and a control space of the main valve. Another throttling point takes place also in the connection between the other control space and the pilot valve. An immediate connection is provided between the main pressure reducing valve and its pilot valve and communicates with a source of pressure fluid medium. Nonetheless, there is no immediate connection between the consumer and the pilot valve. The disadvantage of such prior-art designs is in the fact that the response of the valve is unsatisfactory and depends excessively on the amount of pressure and rate of flow of the pressure medium.